I have an 8 hour layover in early November from 9 am to 5 pm. I have had long layovers there before and have been to Frankfurt and Mainz. (Loved Mainz). Was thinking a day in Wiesbaden. Thoughts and suggestions ?
Try Anschafenburg. You can get there on the train easy.
I would not go to Aschaffenburg, it is too far away for such a short layover.
Have you really seen all of Frankfurt and Mainz? What about all of the museums that are there. In Nov. you may want to do an indoor activity on your layovers. What have you already seen in both of these cities? If you have only been there on layovers, you have haven't had time to see that much.
Wiesbaden is lovely but can't think of anything special to do there other than stroll around, visit the Marktkirche, perhaps the thermal baths?
What are your interests? Is your next flight to N. America or inter-Europe?
Aschafenburg is just as far from Frankfurt as Mainz. Of course you could go to Hanau which is half way there too. Nice old town and worth a 3-4 hour stay.
Heading back to US
In Mainz I have been to the Gutenberg and ancient shipbuilding museums. Both great. In Frankfurt I probably haven’t seen a ton. It was very early. Walked through the old part of town. Saw Dom. Etc.
Major interests include ancient and medieval history and wine.
It takes well over an hour to get to Aschaffenburg from the airport. Frankfurt is 11 min. away and Mainz a bit less than 30 min.
Consider going to Frankfurt Höchst. Catch the bus that stops right outside of B-1, where the Meeting Point is located in terminal 1.
Höchst has one of the oldest churches in Germany (Justinus church consecrated in 850), about 400 half-timbered houses and is part of the Half-Timbered route. If you are there on a Tues. Fri. or Sat. they have a wonderful Farmers market as well as a market hall. Great restaurants along the plaza next to their little schloss. Dry moat to walk through. St. Josephs has a beautiful art-deco decor.
Other sites to visit in Frankfurt itself might be the Karmeliter Cloister, Alte Nikolai, the Jewish Holocaust Memorial Wall, the Judengasse Museum, the Klein Markt Halle, the Tuetonic Order of Knights Church, and of course our new Alt Stadt with the archeology of Franconoford. Thurs. Fri. and Sat. there are nice Farmers markets in the city center.